Throttle/Pedal Position Sensor/Switch “A” Circuit Low Input
Our emissions expert has put together the following information about the P0122 fault code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the code.
OBD II Fault Code
OBD II P0122
Fault Code Definition
Code P0122 is triggered when the voltage output from the Throttle/Pedal Position Sensor/Switch to the PCM is too low.
The Throttle Position Sensor/Switch is located on the Throttle Body of the Intake Manifold and the Pedal Position Sensor/Switch is located on the Accelerator Pedal. These sensors provide precise input from the driver’s foot in terms of how much power is needed—and how urgently—from the engine.
As the Throttle Position Sensor is rotated from its base resting position to full acceleration, it sends a increasing voltage signal to the Powertrain Control Module (PCM). This decreasing or increasing voltage signal is used by the PCM to manage the Air Fuel Ratio and Spark Timing of the engine as well as other emissions system components.
Check Engine Light will illuminate
In many cases, no abnormal symptoms may be noticed
In some cases, the engine may be hard starting
In some cases, the engine may hesitate during acceleration
Common Problems That Trigger the P0122 Code
Defective Throttle Position Sensor or Switch
Torn or jammed floor mats
Faulty or corroded Throttle/Pedal Position Sensor/Switch wiring or connections
Throttle or Pedal Position Sensor is replaced when the real problem is a poor connection or chafed wiring
Pedal Position Sensor is replaced when the real problem is torn or damaged floor mats
Some recommended troubleshooting and repair steps are:
Carefully check the throttle position sensor (TPS), wiring connector, and wiring for breaks, etc. Repair or replace as necessary
Check the voltage at the TPS (refer to a service manual for your vehicle for specific information). If the voltage is too low that is indicative of a problem. Replace if necessary.
If recently replaced the TPS may need to be adjusted. On some vehicles the installation instructions call for the TPS to be properly aligned or adjusted, consult a repair manual for specifics.
If there are no symptoms at all, the problem may be intermittent and clearing the code may resolve the issue temporarily. If this is the case then you should definitely check the wiring to be sure it’s not rubbing on anything, grounding, etc. The code may come back.
Other TPS sensor and circuit related DTCs: P0120, P0121, P0123, P0124
Other DTC ranges are defined for either manufacturer specific codes or under the control of SAE (Society of Automotive Engineers) and not yet defined. This section documents these additional ranges. Refer to your vehicle’s repair manual for manufacturer specific Diagnostic Trouble Codes.
P1XXX Manufacturer Controlled
P10XX Fuel and Air Metering and Auxiliary Emission Controls
P11XX Fuel and Air Metering
P12XX Fuel and Air Metering
P13XX Ignition System or Misfire
P14XX Auxiliary Emission Controls
P15XX Vehicle Speed, Idle Control, and Auxiliary Inputs
P16XX Computer and Auxiliary Outputs
P2XXX SAE Controlled DTCs
P20XX Fuel and Air Metering and Auxiliary Emission Controls
P21XX Fuel and Air Metering and Auxiliary Emission Controls
P22XX Fuel and Air Metering and Auxiliary Emission Controls
P23XX Ignition System or Misfire
P24XX SAE Reserved
P25XX SAE Reserved
P26XX SAE Reserved
P27XX SAE Reserved
P28XX SAE Reserved
P29XX SAE Reserved
P3XX Manufacturer Controlled and SAE Reserved
P30XX Fuel and Air Metering and Auxiliary Emission Controls
P31XX Fuel and Air Metering and Auxiliary Emission Controls
P32XX Fuel and Air Metering and Auxiliary Emission Controls
P33XX Ignition System Misfire
P34XX SAE Reserved
P35XX SAE Reserved
P36XX SAE Reserved
P37XX SAE Reserved
P38XX SAE Reserved
P39XX SAE Reserved